From: Jens Axboe <axboe@kernel.dk>
To: "linux-block@vger.kernel.org" <linux-block@vger.kernel.org>
Subject: [PATCH] blktrace: fix trace mutex deadlock
Date: Sun, 19 Nov 2017 11:52:55 -0700 [thread overview]
Message-ID: <a0e84358-d9af-4999-4512-3219f0d558ac@kernel.dk> (raw)
A previous commit changed the locking around registration/cleanup,
but direct callers of blk_trace_remove() were missed. This means
that if we hit the error path in setup, we will deadlock on
attempting to re-acquire the queue trace mutex.
Fixes: 1f2cac107c59 ("blktrace: fix unlocked access to init/start-stop/teardown")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index 206e0e2ace53..f224985de5fa 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -591,7 +591,7 @@ static int __blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
return ret;
if (copy_to_user(arg, &buts, sizeof(buts))) {
- blk_trace_remove(q);
+ __blk_trace_remove(q);
return -EFAULT;
}
return 0;
@@ -637,7 +637,7 @@ static int compat_blk_trace_setup(struct request_queue *q, char *name,
return ret;
if (copy_to_user(arg, &buts.name, ARRAY_SIZE(buts.name))) {
- blk_trace_remove(q);
+ __blk_trace_remove(q);
return -EFAULT;
}
--
Jens Axboe
reply other threads:[~2017-11-19 18:52 UTC|newest]
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